1 /* $OpenBSD: select.c,v 1.4 2018/04/26 15:55:14 guenther Exp $ */ 2 /* 3 * Copyright (c) 1993, 1994, 1995, 1996 by Chris Provenzano and contributors, 4 * proven@mit.edu All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Chris Provenzano, 17 * the University of California, Berkeley, and contributors. 18 * 4. Neither the name of Chris Provenzano, the University, nor the names of 19 * contributors may be used to endorse or promote products derived 20 * from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL CHRIS PROVENZANO, THE REGENTS OR 26 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 27 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 28 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 29 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 30 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 31 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 32 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Rudimentary test of select(). 37 */ 38 39 #include <sys/types.h> 40 #include <sys/time.h> 41 #include <errno.h> 42 #include <fcntl.h> 43 #include <pthread.h> 44 #include <pthread_np.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <unistd.h> 48 #include "test.h" 49 50 #define NLOOPS 10000 51 52 int ntouts = 0; 53 54 static void * 55 bg_routine(void *arg) 56 { 57 char dot = '.'; 58 int n; 59 60 SET_NAME("bg"); 61 62 /* Busy loop, printing dots */ 63 for (;;) { 64 pthread_yield(); 65 write(STDOUT_FILENO, &dot, sizeof dot); 66 pthread_yield(); 67 n = NLOOPS; 68 while (n-- > 0) 69 pthread_yield(); 70 } 71 } 72 73 static void * 74 fg_routine(void *arg) 75 { 76 int flags; 77 int n; 78 fd_set r; 79 int fd = fileno((FILE *) arg); 80 int tty = isatty(fd); 81 int maxfd; 82 int nb; 83 char buf[128]; 84 85 SET_NAME("fg"); 86 87 /* Set the file descriptor to non-blocking */ 88 flags = fcntl(fd, F_GETFL); 89 CHECKr(fcntl(fd, F_SETFL, flags | O_NONBLOCK)); 90 91 for (;;) { 92 93 /* Print a prompt if it's a tty: */ 94 if (tty) { 95 printf("type something> "); 96 fflush(stdout); 97 } 98 99 /* Select on the fdesc: */ 100 FD_ZERO(&r); 101 FD_SET(fd, &r); 102 maxfd = fd; 103 errno = 0; 104 CHECKe(n = select(maxfd + 1, &r, (fd_set *) 0, (fd_set *) 0, 105 (struct timeval *) 0)); 106 107 if (n > 0) { 108 /* Something was ready for read. */ 109 printf("select returned %d\n", n); 110 while ((nb = read(fd, buf, sizeof(buf) - 1)) > 0) { 111 printf("read %d: `%.*s'\n", nb, nb, buf); 112 } 113 printf("last read was %d, errno = %d %s\n", nb, errno, 114 errno == 0 ? "success" : strerror(errno)); 115 if (nb < 0) 116 ASSERTe(errno, == EWOULDBLOCK || 117 errno == EAGAIN); 118 if (nb == 0) 119 break; 120 } else 121 ntouts++; 122 } 123 printf("read finished\n"); 124 return (NULL); 125 } 126 127 int 128 main(int argc, char *argv[]) 129 { 130 pthread_t bg_thread, fg_thread; 131 FILE * slpr; 132 133 /* Create a fdesc that will block for a while on read: */ 134 CHECKn(slpr = popen("sleep 2; echo foo", "r")); 135 136 /* Create a busy loop thread that yields a lot: */ 137 CHECKr(pthread_create(&bg_thread, NULL, bg_routine, 0)); 138 139 /* Create the thread that reads the fdesc: */ 140 CHECKr(pthread_create(&fg_thread, NULL, fg_routine, (void *) slpr)); 141 142 /* Wait for the reader thread to finish */ 143 CHECKr(pthread_join(fg_thread, NULL)); 144 145 /* Clean up*/ 146 CHECKe(pclose(slpr)); 147 148 SUCCEED; 149 } 150